Mold and process for forming porcelain insulators therein



y E. 1. TAYLOR. MOLD AND PROCESS FOR FORMING PORCELAIN INSULATORS THEREIN.

APPLICATION FILED AUG. 9. I9I9.

Patented Sept. 7, 1920.

Erme by 1165 abby lPA'IiazNT OFFICE.

ERNEST Jj.; TAYLOR, OF EVERETT, MASSACHUSETTS.

MOLD AND PROCESS FOR. FORMING PORCELAIN INSULATORS THEREIN.

Specification of Letters Patent.

Patented Sept. 7, 1920.

Application filed August 9, 1919. Serial No. 316,366.

To all whom t may cof/cera Be it known that I, ERNEST J. TAYLOR, a citizen of the VUnited States, residing at Everett, in the county of Middlesex and State of Massachusetts, have invented new and useful Improvements in Molds and Processes for Forming Porcelain Insulators T herein, of which the following is a specification. M

This invention relates to molds and to the method of forming porcelain insulators for spark plugs by means of said molds.

lt is the object of the invention to provide a mold in which clay in a plastic state may be placed and formed into insulators, the said insulators being absolutely smooth and free from internal strains which tend to lcause distortion and cracks when the insulators are later removed from the mold and baked in a kiln.

So far as l: am aware up to the present time porcelain insulators for spark plugs have always been formed in split molds and by applying the pressure to the clay laterally of the insulator. This method of forming the insulator has proved unsatisfactory as there is a large percentage of loss caused by imperfections. These imperfections result from various causes.

In a split side-pressure mold it is impossible to mold an insulator without forming a thin fin between the adjacent faces of the mold and when this is removed it results in a rough line on the completed porcelain insulator. Furthermore, if an insulator upon being removed from a side-pressure mold is found to be slightly out of alinement and has to be straightened, or if there have been rough places upon its surface prior to being placed in the kiln, even though the insulator has been lground smooth, when the insulator is subsequently baked said insulator will return to yits former distorted position and i the roughness and other inequalities will reappear. Y

It is an object, therefore, of this invention to so constructthe mold that the pressure upon the clay will be applied endwise of the molded clay, the result beingk that said molded clay maybe removed from the mold free from roughness or internal strains of any kind so that the finished article when baked will be perfect. Y

The invention consists in the combination 'following Ipointed out in the claims thereof.

lline I S and arrangement of parts set forth in the specilication and particularly l'efcrriug to the drawings:

.Figure 1 is a plan View of my improved 'mold is a plan viewA of a modified constriiction ofinold embodying my invention.

Fig. G is a front elevation of the same. Fig. 7 is a plan view of still another embodiment of my invention.

Fig. S is a vertical section taken on the 8 of` Fig. 7. Like numerals refer to like parts throughout the several views of the drawings.

in the drawings, Figs. 1l to l inclusive, 10 represents the main body portion of a mold, the same being constructed in one piece from'any suitable material preferably metal. The upper part of the body portion 1'() has a cylindrical bore 11 which correspends to the diameter of the vcentral portion of an insulator 12. At its lowe'r end the cylindrical bore 11 terminates in a recess 13 which conforms to the shape of an end portion 14 of the insulator 12. An opening 15 extends through the lower end of the body portion 10 of tlie mold and communicates with the recess13, said opening con stituting an air vent, an outlet for the excess of clay 22, and also a means whereby a rod may be inserted., as will hereinafter be more fully explainedf A plurality of other openings 1G communicate with the interior of the body portion 10 and also constitute air vents and outlets for the excess of clay 22.v

A plunger 17 is adapted toV fit the bore 11 of the body portion 10 and slide vertically therein, the downward movement of said plunger 17 in said body portion being limited by a flange 18 which engages the upper end of said body portion. The plunger 17 is provided with a recess 19 which conforms to the shape ofan end portion of the insulator 12. 'l The plunger 17 is also provided with an opening 21 Ywhich communicates with the recess19 and also constitutes an air vent and an outlet for the excess of clay 22; The' Vfollows: A quantity oi clay 22 in plastic state is placed in the bore 11 of the main body portion 10 of the mold. The quantity of clay should be somewhat' in excess of the exact amount required, The plunger 17 is then inserted within the bore 11 and pushed into contact with the clay t22. The mold is then placed under a suitable press and the plunger 17 is forced downwardly until the flange 18v engages the top of the main body portion 10' at which time the entire cavity vupon the interior of the mold should be solidly' filled, anyexcess of clay having been forcedoutwardly through the openings 15,

16 or 21. The air also within the interior of the mold `is forcedl outwardly through the saine openings. y

The pressure upon the clay informing the insulator is appliedendwise of the insulator.

After beingv removedfrom the press a rod 23, illustrated in dotted lines in Fig. 2, is inserted in' either the opening 21 or the opening 15' and said rod isiorced through the clay 22 andvout through the opposite end of the mold.` This will form a hole 24 which will extend entirely through the insulator.

The mold is next placed in a warm location and the clay allowed to dry within the mold until said clay has shrunk suliieiently to be released from the inside surface of the mold. rlhe position of the mold is then reversed rom that illustrated in Fig. 2 and the plungerI 17 withdrawn, the molded clay resting' in the recess 19 of the plunger 17 as illustrated in Fig. Ll. In this manner the molded clay may be removed from the main body portion 10 ol the mold vwithout injuring the same in any way. lllhile resting in the plunger 17 the molded4 clay is allowed to dry until it can be safely handled when it is .removed from the plunger 17 and placed in a kiln and baked.I Clay molded and dried in'this manner will not crack or become distorted as isv the case when thev pressure is applied from the side. i

In Figs. 5 and 6 I have illustrated another embodiment of my invention. vIn this embodiment themain body portion of the mold is constructed iii't'wo parts 25 and 26,-said parts ,being positionedi relatively, to each other by. d Nels 27 and heldtogether byv a pair' of ring 28.., InI other respects the mold illustrated in" Figs. 5 and' is exactly the the mo d previouslyidescribed and the method kemployed molding clay therein islilrewise'exactly the same, except that in this form, the main body portion of the mold may be sepa ated into two parts if desired by removing the rings 28,.

in Figs. 7 and 8 l have illustrated still another embodiment of my invention wherein l have' foruied7 a multiple mold employing a single body portion 29. In other respects the mold is exactly the same as the mold illustrated and described in connection' with Figs. 1 to 4 inclusive and the method employed in forming the insulator and drying the same is exactly the same as the method in the preferred embodiment of my invention.

It is also evident that a multiple mold may be constructed with a body portion termed in two separate parts suitably fastened together without departing from the spirit of my invention. l

liaving thus specilically described my in vention what l claim and desire by Letters kPatent to secure is g, in combination,- a main body portion, said main body poi-tien being provided with a longitudinally entended bore and also being provided with vents, and a plunger adaptedto slide within said bere and into endwise engagement with plastic material contained. within said bore, where by said material may be compressed endwise into a pre-determined sha-pe, said plunger also being adapted te vertically position said 1. A mold ha vino' compressed material and aiter the same l been removed Ylrom said mold. Y 2. A mold having, in combination, a main body portion, said main body portion being provided'with a longitudinally extended bore and also being provided with vents, and a plunger having a recess in its forward end and adapted to slide within said bore and into endwise engagement with plastic material contained within said bore, whereby said material may be compressed en dwise into a predetermined shape and subsequently vertically positioned in the recessed end of said plunger after being removed from said bore. n y

3'.' The herein described method of torming insulators for spark plugs which consists in iii-st inserting a-mass of plastic material in a longitudinally extended bore provided in the main body portion of av mold, second, submitting said plastic mass to endwise pressureby means of a plunger which slidablylits said bore and has a recess in its forward end' whereby said plastic mass may be compressed endwise within said bore and recess, and` third, allowing said compressed mass. to dry withinsaid mold under the in'- luencfe 'of heat applied to said mold.

4. The herein described method of form ing insulators for sparlrplugs which consists in lirst inserting a mass of plastic material in a longitudinally extended bore provided in the main body portion of a mold7 second', submitting said plastic mass to e'ndwise pressure by means of a plungerv which slidably lits said bore and has a recess in its forward end whereby said plastic mass may be compressed endwise within said bore and recess, third, allowing said compressed mass to partially dry within said mold um der the intluence o'l' heat applied to .l mold, and fourth, removing said plunger' from the main body portion of said mold with the compressed mass retained in the recess in said plunger' and allowing said compressed mass to dry still iurther while being supported within said recess in said plunger,

5. 'l`he herein described method ot formingV insulators Ylor sparii plugs which consists in lirst inserting a mass of plastic material in a longitudinally extended bore provided in the main body portion of a mold, said mold being provided with suitable vents, second, submitting said plastic mass to endwise pressure by means ot a plunger which slidably iits said bore and has a recess in its orward end whereby said plastic mass may be compressed enewise within said bore and recess,- the excess of plastic material escaping through said vents, third, allowing said compressed mass to partially dry within said mold under the influence of heat ap plied to said mold, and fourth, removing said plunger' from the main body portion of said mold lwith the compressed mass retained in the recess in said plunger and allowing said compressed mass to dry still further while being supported within said recess in said plunger.

(3. rihe herein described method of' 'forming insulators for spark plugs which consists in i'irst inserting a mass olf plastic material in a longitudinally lextended bore provided in the main body portion ot a mold, said mold being provided with suitable vents, second, submitting said plastic mass to. endwise pressure by means of a plunger which slidably lits said bore and has a recess in its forward end whereby said plastic mass may be compressed endwise within said bore and recess, the excess olf plastic material escaping through said vents, third, 'orcing a rod through said compressed mass within said mold and removing the same, thereby forming a hole through said compressed mass, fourth, allowing said compressed mass to partially dry within said mold, and fifth, removing said plunger from the main body portion oi said mold with the compressed mass retained in the recess in said plunger and allowing said compressed mass to dry still further while being supported within said recess in said plunger.

ln testimony whereof I have hereunto set my hand in presence of two subscribing witnesses.

ERNEST J. TAYLOR.

Witnesses FRANKLIN E. Low, HERMAN R. I-IorriirAN. 

